Blockchain-assisted searchable attribute-based encryption for e-health systems

The Internet of Things (IoT) is becoming increasingly popular for transmitting massive data in a network. With a limited supply of IoT devices, utilizing cloud storage is considered to be an optimal way of processing data. Although cloud computing provides an efficient means of data storage and secure sharing in resource-limited devices, it is still a challenge to enable end users to publish search queries and implement fine-grained access control over a ciphertext at the same time. Blockchain-assisted searchable attribute-based encryption (SABE) can achieve data confidentiality and fine-grained access control. In our work, we present blockchain-assisted SABE for e-health systems. Our framework not only combines the advantages of attribute-based encryption (ABE) and blockchain technology but also supports hidden policies. A rigorous security proof shows that our scheme can achieve the known security under a chosen keyword attack. An experiment indicates that the proposal is suitable for e-health systems.